It’s safe to say spring is officially here.

The astronomical marker of the season, the vernal equinox, is today, March 20, at 11:15 a.m. CDT.

But meteorological spring began weeks ago on March 1.

Today’s vernal equinox marks the time when the sun crosses over the equator and the length of days and nights will be almost equal.

That’s where its name came from, the Latin words aequus (equal) and nox (night).

The days have been growing steadily longer, but today won’t have exactly 12 hours of sunlight.

Local times vary, but for example, in Birmingham today there will be 12 hours, seven minutes and 58 seconds of daylight.

But the closest that area came to equal day and night was on March 16, when there was 11 hours, 59 minutes and 36 seconds of light. 

The days will grow progressively longer until the summer solstice, which in 2018 falls on June 21.

This is the first of two annual equinoxes. The fall — or autumnal — equinox falls on or around Sept. 22 each year.

In 2018 it will be on Sept. 22 at 8:54 p.m.

Meteorological spring lasts exactly three months: March, April and May.